The invention relates to a device for pivotally connecting a wiper blade for use on motor vehicle windows to a wiper arm. In a known device of this type (German Utility Model 81 19 737), a pivot pin is formed onto a wiper arm made of plastic and, by means of a longitudinal slit, can engage in detent fashion in a transverse bore disposed in a frame part which is made of an elastic plastic and is used as a wiper strip support. This presents difficulties in the material selection both for the wiper arm and for the frame part. The wiper arm, for example, must have the required rigidity, which places limitations on the material selection for the frame part as a sliding partner for the pivot pin. Contrary demands are placed on the frame part itself. On one hand, it should be possible to elastically widen the narrow point in the longitudinal slit to such a degree that the pivot pin can engage in detent fashion in the transverse bore and is securely held during wiper operation and on the other hand, in a plane perpendicular to the window to be wiped, the frame part should adapt in a spring-elastic manner to the window surface and should be relatively stiff in the wiping movement that occurs lateral to the longitudinal direction of the wiper blade. All of these requirements can be accommodated only be making unsatisfactory compromises.
In the device according to the invention, it is possible to manufacture the wiper strip support out of a material, for example, a spring band steel, which fulfills all of these stated requirements. For the coupling element disposed on this wiper strip support, there are a multitude of plastics available whose properties are favorable as a sliding partner for the pivot bolt and also for the ability of the narrow point to be elastically spread open.
In order to achieve a particularly low profile of the wiper blade together with the connecting device, the support has two elongated support strips comprised of a spring-elastic metal, which are disposed in longitudinal grooves that open toward the longitudinal sides of the wiper strip, wherein over at least one longitudinal section, the support strips respectively protrude laterally out from the longitudinal grooves with an edge strip so that the coupling element can be secured to the two edge strips of the support strips.
In order to secure the support strips in their longitudinal grooves lateral to their longitudinal span, claw-like projections that protrude toward the window are disposed on the longitudinal sides of the coupling element and on its underside oriented toward the support strips, and with one L leg, each of these claws intersects a plane in which the two support strips are disposed and the respective other L legs extending from the first L legs are directed toward each other and engage under the edge strips of the support strips. In this connection, it is unimportant whether the other L legs come into direct contact with the underside of the support strips or whether there is an intermediary layer, for example an extension of the wiper strip, between these support strips and the edge strips.
In an improvement of the invention, the device is provided with locking means for securing the operating position between the transverse bore and the pivot pin. This permits a higher degree of operational reliability for the pivotal connection between the wiper arm and wiper blade.
Suitably, the locking means have a stop shoulder disposed on the wiper arm, pointing away from the window, and this stop shoulder is associated with an opposing shoulder of the wiper blade oriented toward the window.
A particularly simple and compact embodiment of the connecting device is produced if the stop shoulder is embodied on an angular projection of the wiper arm that protrudes toward the window.
If the wiper arm, at least in the vicinity of the pivot bolt, has two side walls spaced apart from and parallel to each other, which protrude toward the window, each of which secures an end of the pivot bolt, the pivot bolt, which is produced as a separate component, can also be made of a material that is particularly suited for its function.
In order to achieve a stable wiper arm, which simultaneously protects the connecting device from environmental influences, and thereby significantly extends its service life, the side walls are constituted by the U legs of the wiper, which has a U-shaped cross section, at least in parts, wherein the projection is disposed on the inside of the U base oriented toward the window and the U legs encompass longitudinal sides of the coupling element.
A particularly favorable guidance of the wiper blade lateral to its longitudinal span and thereby a smooth wiper operation is produced if the distance between the U legs is matched to the distance between two opposite longitudinal side faces of the coupling element.
To further improve the protection from environmental influences, the U base of the wiper arm covers over the narrow point of the transverse bore in the operating position.
A particularly simple, stable, and inexpensive design of the coupling element is achieved if, in a further embodiment of the invention, the coupling element has a base plate provided with claw-like projections, which supports a box-like structure, if the side walls extending in the longitudinal direction of the wiper blade are also connected to each other by a support block that contains the transverse bore, and if a slit remains between the top wall of the structure and the support block. In this connection, the support block ensures the strength of the structure and the slit permits a passage of the angular arm projection so that its stop shoulder can be brought into its operating position.
If a recess is disposed between the support block and the base plate of the coupling element, then there is inevitably an insertion space for the one leg of the angular projection disposed on the wiper arm.
In a continuation of this embodiment, with corresponding adaptation, the opposing shoulder of the wiper blade is inevitably produced on the underside of the support block.
Particular additional measures for maintaining an operationally reliable pivotal connection can be eliminated if the stop shoulder of the wiper arm is disposed directly opposite and in immediate vicinity of the opposing shoulder of the wiper blade when the wiper arm is in the initial operating position.
In a wiper blade with a wind deflecting strip that extends beyond the upper band surface of the support element, it is suitable to dispose the coupling element in a recess of the wind deflecting strip.
In order to improve the installation process, in a wiper blade with a wind deflecting strip, viewed in the longitudinal direction of the wiper blade, the box-like structure of the coupling element is offset in relation to its base plate to the side toward which a flow bevel embodied on the wind deflecting strip points.
In order to improve the contact behavior of the wiper blade against the window even at high driving speeds, the U leg of the wiper arm that the driving wind predominantly flows against is provided with a bevel that serves as a wind deflecting strip, wherein in order to maintain a low profile of the wiper blade and coupling element connected to the wiper arm, the part of the box-like structure disposed in the vicinity of this bevel is adapted to the course of this bevel.
Other advantageous improvements and updates of the invention are disclosed in the following description of an exemplary embodiment shown in the accompanying drawings.